The present invention relates to a computation system for calculating the electrical energy of an alternating current flowing in at least one secondary electrical conductor being electrically connected to a primary electrical conductor, the primary conductor and each secondary conductor having substantially the same alternating voltage, the alternating current having at least one phase.
This calculation system includes:                a first device comprising a radio transmitter, a measuring member for measuring the voltage of the primary conductor, first sampling means for sampling the value of the measured voltage, message transmitting means for transmitting, following a period of transmission, of a first message, the transmission period corresponding to a multiple of voltage periods, the voltage period being equal to the inverse of the frequency of the alternating voltage, and voltage determination means for determining a set of at least one variable value representative of the measured voltage, said data set being determined based on the value of the voltage measured during a given transmission period, with the first message containing said data set;        at least one second device comprising a current intensity sensor for determining the intensity of the current flowing in the corresponding secondary conductor, second sampling means for sampling the value of the measured intensity; and        at least one computing member for calculating the electrical energy for each phase of said current flowing in the corresponding secondary conductor, the computing member being connected to at least one corresponding second device and including a radio receiver and message reception means for receiving the first message, each computing member being configured for calculating a value for the electrical energy during the given transmission period on the basis of said data set contained in the first message and samples of the intensity associated with the given transmission period.        
The present invention also relates to an electrical cabinet including a panel comprising output electrical conductors, and such a computation system.
The present invention also relates to a transformer substation for transformation of an electric current having a first alternating voltage into an electric current having a second alternating voltage, this transformer substation including such an electrical cabinet, an input panel including at least one input electrical conductor configured for being connected to an electrical network, the input electrical conductor having the first alternating voltage, the panel of the electrical cabinet forming an output panel wherein the corresponding output conductors have the second alternating voltage. The transformer substation further includes an electrical transformer connected between the input panel and the output panel, the transformer being configured for transforming the current having the first alternating voltage into the current having the second alternating voltage.
This present invention also relates to a method for calculating the electrical energy by using such a computation system.
A computation system of the aforementioned type is already known from the document WO A1 2013/017663. The computation system includes a first device, referred to as primary module, comprising a radio transmitter, a measuring member for measuring the voltage of the primary conductor, the sampling means for sampling the value of the measured voltage, and the message transmitting means for transmitting of a first message. The period of transmission of the first message is equal to one second, and corresponds to 50 voltage periods, with the voltage period being equal to the inverse of the frequency of the alternating voltage, which is 20 ms. The computation system also includes a plurality of second devices, referred to as secondary modules, each comprising a current intensity sensor for determining the intensity of the current flowing in the corresponding secondary conductor, the sampling means for sampling the value of the measured intensity, and a computing member for calculating the electrical energy for each phase of said current flowing in the corresponding secondary conductor.
In order to calculate the electrical energy, the computing member calculates, at each voltage period, that is to say at time intervals of 20 ms, an active power based on the values of the measured intensities and the voltage values received in the first message. The active energy is calculated by incrementing for each phase, a positive energy counter when the calculated active power is positive, and incrementing a negative energy counter when the calculated active power is negative. The electrical energy is calculated for the given transmission period and on the basis of a set of variable values representative of the measured voltage. This data set is determined for a voltage period selected from among the plurality of voltage periods occurring during the given transmission period, in order to limit the amount of data transmitted by radio waves between the elements of the system for calculation of the electrical energy.
However, the calculation of the electrical energy by means of such a computation system is not optimal.